The present invention relates to concrete joint sealing devices, and more particularly, to a waterstop/mechanical seal for use with an expansion board.
When concrete slabs are positioned adjacent to one another, the space between the slabs forms an alluring trap for liquid accumulation. Liquid accumulation detrimentally affects the concrete causing deterioration and buckling. In addition to concrete damage, the collection of liquids degrades expansion boards which are placed between the slabs to accomodate joint expansion.
Several attempts have been made in the prior art to extend the life of concrete by preventing liquid permeation into concrete joint areas and expansion boards. One method is to chemically treat the expansion boards placed between adjacent slabs of concrete. The chemicals waterproof the board, making it resistant to liquid penetration. Unfortunately, despite the preservation benefits of chemicals, they damage the environment and sometimes discolor the boards and the surrounding concrete.
Another method of protecting the joint areas includes covering the joints with concrete joint sealing devices generally consisting of a caulking or sealant material. These devices cover the joints and restrict the entry of liquid between adjacent concrete sections but do not specifically protect the expansion boards. In addition, most of the sealants used in these devices have minimal durability and elasticity. The sealants do not always endure expansion, contraction and other movements of the concrete that result from outside pressures. Sealants also fail due to improper preparation and poor handling to the concrete. Furthermore, some of the sealants used in these devices react with adjacent metal structures, reinforcing bars or additives incorporated into the concrete. Occasionally, these reactions result in concrete and expansion board deterioration.
While all of the aforementioned examples have solved some of the problems associated with concrete joint areas, several limitations remain which have not been solved by prior art designs.